Automatic refrigeration and defrost system



Jan. 8, 1963 M. KAPEKER 3,071,935

' AUTOMATIC REFRIGERATION AND DEFROST SYSTEM Filed April 8. 1959 COIL 407 HEAIT ExcHAueE:

7Z7 ,8 DRIP PAN T 17 2% COMPRESSOR 1| I FIG. l. 60 I 42b 5s 1 i! ii I i I: i INVENTOR. i 2 MARTIN KAPEKER United States Patent Ofifice 3,071,935 PatentedJan. 8, 1963 3,071,935 AUTOMATIC REFRIGERATION AND DEFROST SYSTEM Martin Kapeker, 7714 Bay Parkway, Brooklyn, N.Y. Filed Apr. 8, 1959, Ser. No. 805,066 8 Claims. ((31. 62-155) This invention relates to the field of refrigeration, and has for its objective the provision of a superior automatic apparatus for use in refrigeration and for the hot gas defrosting of refrigerator evaporator coils.

Presently there are numerous and varied systems, both manual and automatic, employing the hot refrigerant gases to defrost these evaporator coils at periodic intervals. Most of these systems provide for a defrost cycle which carries the hot refrigerant gases directly from the compressor to the evaporator coils and returns them to the compressor, avoiding the normal refrigerating cycle. In such a process the hot gases pass through low temperatures areas which condense a considerable portion of the gases into liquid, as well as lowering the temperature of the gases with resultant decrease in efficiency, and in the return to the compressor of liquid refrigerant eventual damage to the compressor results, in addition to the ob vious reduction in the efiiciency of the defrost system. This is more particularly true where the refrigerator or refrigeration system is located in a low temperature or sub-freezing area.

In the face of this problem attempts have been made in the past to provide, in the return of the gases from the evaporator coils to the compressor, some means to avoid the temperature reduction and the consequent condensation of the gases. One of these means has taken the form of an intermediate vessel to retard the flow of liquid and thus facilitate the movement of the gases. Another method has provided a heating means along a portion of the return conduit, from the evaporator coils to the compressor, to raise the temperature of the return conduit and consequently of the refrigerant passing through it at the area.

These methods, however, have been only partially successful, and have reduced but not eliminated the problem. Additionally, the means so employed have been integrated with the apparatus to such an extent that repairs and servicing have been both time consuming and expensive.

One of the important objects of my invention, therefore, is to provide an automatic hot gas defrost system which will completely eliminate the return of refrigerant liquid to the compressor.

A second important object of my invention is to provide an automatic hot gas defrost system of increased efliciency.

A third important object of my invention is the provision of an automatic hot gas defrost system which can be used with various old as well as new refrigeration installations, such as coils, blowers, plates, home freezers, refrigerators, etc.

A fourth important object of my invention is the provision of an automatic refrigeration and hot gas defrost system which is operable in extremely low temperature areas.

A fifth important object of my invention is the provision of an automatic hot gas defrost system which is fully accessible and entirely automatic.

Still another important object of my invention is th provision of an automatic hot gas defrost system which is inexpensive to manufacture, and simple to install and service.

These and other salient objects, advantages and functional features of my invention, together with the novel features of construction and arrangement of parts, will be more readily apparent from an examination of the follow- End ing description, taken with the accompanying drawings, wherein:

Fig. 1 is a diagrammatic view of a common form of refrigeration system including an automatic hot gas defrosting system constructed according to my invention; and

Fig. 2 is an enlarged cross-sectional view of a preferred form of the re-evaporator chamber, constructed according to my invention, and constituting the novel feature thereof.-

Similar reference characters designate similar parts throughout the different views.

Illustrative of the embodiment shown, and referring to FIG. 1, there is shown a usual refrigeration system which includes a compressor 10, a condenser 12, a re-' ceiver 14, a heat exchanger 16, an expansion valve 18, a fan 20 and'evaporator coils 22, of standard construction and design requiring no further description. Addi tionally, in accordance with my invention, there is provided a re-evaporator chamber 24, which will hereinafter be more fully described.

In the operation of the normal refrigeration cycle the refrigerant in gas form is compressed within the compressor 10. It is then directed through a conduit 26 to the condenser 12, where it is condensed into liquid, passing through a conduit 28, past a control valve 30, into the liquid receiver 14. From the receiver 14 the refrigerant liquid is conducted past a service valve 32 and through a conduit 34 until it reaches the expansion valve 18 where it is expanded into low pressure liquid and directed through the evaporator coils 22. The fan 20, electrically activated by means of a timer switch 38, of standard construction and design, provides air circulation around the evaporator coils 22. From the evaporator coils 22 the refrigerant is directed through a conduit into the heat exchanger 16 from which it is drawn through a suction line 42a into the re-evaporator chamber 24, from which the refrigerant gas is drawn through a suction line 4212 into the compressor 10, from which the cycle is repeated.

For the defrost system there is provided a secondary cycle which comprises a hot gas conduit 44 leading from the compressor conduit 26, a drip coil 46 leading from the conduit 44 into the evaporator coils 22 and controlled by a check valve 48, a drip pan 50 and a drain pipe 52, all of standard construction and design and requiring no further description herein. The conduit 44 is provided with a valve 54, which is closed during the normal refrigeration cycle and which is activated by a solenoid 56 energized through the timer switch 38, as will be hereinafter explained. The re-evaporator chamber 24 and suction lines 42a and 42b, as well as the heat exchanger 16, con stitute parts of the defrost cycle.

The re-evaporator chamber 24 is preferably cylindrical in shape and is provided with an electric heater element 58 secured through its base and extending vertically in the chamber 24, and controlled by the timer switch 38. A temperature sensing element 60, connected to a tem perature controller 62 likewise activated by the timer switch 38, is provided secured to the side of the chamber 24 and extending into the chamber 24, as shown. The chamber 24 is also provided at its base with an oil conduit 64 leading therefrom into the suction line 42b.

Electric current for the operation of the fan 20 and the activation of the defrost cycle is provided by a circuit including the timer switch 38, of standard construction and design, a power line 66 leading from an electric source (not shown) to the timer switch 38, branch lines 70, 72 and 74 leading respectively to the fan 20, solenoid 56 and heater element 58, and branch lines 76, 78 and 80 returning respectively from the fan 20, solenoid 56 and heater element 58 to the main power line 68 connected to the current source. The temperature controller 62 is connected to the power line St to regulate the temperature within the re-evaporator chamber 24 so as to maintain a constant temperature therein.

In the operation of the normal cycle of refrigeration, as has been described above, the fan 20 is energized by the timer switch 38, While the solenoid 56 and heater element 58 are de-energized. For the operation of the defrost cycle, at periodic, preselected intervals the timer switch 38 turns off the fan 20 and simultaneously energizes the solenoid 56 to open the valve 54, and energizes the heater element 58. The hot gas refrigerant from the compressor passes through the hot gas conduit 44, bypassing the condenser 12, and is directed through the valve 54, through the drip coil 45, through the evaporator coils 22 and through the heat exchanger 16, and is drawn through the suction line 42a from which it passes into the re-evaporator chamber 24, the hot gas therefrom being drawn into the suction line 42b and directed therein back into the compressor 10, from which the cycle is repeated until the defrosting process is completed. In the cycle of the hot refrigerant gas, both in the defrosting of the evaporator coils 22 and in passing through such parts of the system as are located in low temperature areas, some of the gas is condensed into liquid. Commonly some of the oil from the compressor 10 passes into the defrost system as well. The liquid refrigerant and oil passing through the defrost system are drawn with the refrigerant gas into the re-evaporator chamber 24, from which the gas is drawn back into the compressor drawn out through the suction line 42b, While the oil therein drains back into the compressor through the oil conduit 64. In this manner no liquid refrigerant returns to the compressor 10, While at the same time the action of the heater element 58 serves to increase the temperature of the gas refrigerant and thereby increase the efiiciency of the defrost cycle.

The defrost cycle is continued for the predetermined time necessary to complete defrosting, at the end of which time the timer switch 38- automatically turns off the solenoid 56 to close the valve 54, and cuts off the current to the heater element 58, simultaneously reactivating the fan 20, whereupon the normal refrigeration cycle is again put in operation.

In the defrost cycle the hot gas passing through the drip coil 46, located within the drip pan 50, facilitates the melting of the accumulated ice and its elimination through the drain pipe 52.

Thus it will be seen that the interposition of the reevaporator chamber 24, with its heater means 58, between the suction line 42a and the suction line 42b, in the manner shown, successfully prevents the return of any refrigerant liquid to the compressor 10, both in the defrost cycle and the normal refrigerating cycle. The chamber 24, with its controlled heater element 58, also serves to increase the temperature of the returning refrigerant gas and thus increase the efliciency of the defrost cycle. This is of particular value and importance where the refrigerator system is located in extremely low or sub-freezing temperature areas, since the condensation of the refrigerant gases passing through such areas is prevented by the heat generated in the chamber 24. The provision in the chamber 24 for the draining of any incidental oil, passing through the conduits, back into the compressor 10, insures the removal of this incidental oil from the systems and prevents loss of the oil.

It will be further seen that the provision of the reevaporator chamber 24 adjacent the compressor 10 permits easy access thereto for installation with both old and new refrigerator systems, and facilitates servicing and repair, should same become necessary.

The embodiment above described, and shown by the drawings, is by way of illustration only, and various changes may be made in the construction, composition and arrangement of parts without limitation upon or departure fro-m the spirit and scope of the invention, or sacrificing any of the advantages thereof inherent therein, all of which are claimed.

Having described my invention, I claim:

1. In an automatic refrigeration and hot gas defrost system wherein the refrigeration system comprises a compressor, a condenser, a liquid receiver, an expansion valve, evaporator coils and a heat exchanger, with interconnecting conduits therefore and conduit means for return of the refrigerant to the compressor, and the hot gas defrost system comprises interconnecting conduit means, including a valve controlled by a solenoid, adapted to bypass the condenser and to divert the refrigerant gas directly from the compressor to the evaporator coils, with conduit means to return the refrigerant to the compressor, and an automatic timer switch connected with an electric circuit and adapted to activate the systems alternately at pre-selected intervals; the improvement which comprises a re-evaporator chamber disposed intermediate the return conduit adjacent the compressor and adapted to receive the returning refrigerant and to retain the liquid portion thereof, and heating means provided within the chamber in direct contact with the refrigerant and adapted to vaporize the liquid refrigerant therein during activation of the defrost system.

2. In an automatic refrigeration and hot gas defrost system wherein the refrigeration system comprises a compressor, a condenser, a liquid receiver, an expansion valve, evaporator coils and a heat exchanger, with interconnecting conduits therefore and conduit means for return of the refrigerant to the compressor, and the hot gas defrost system comprises interconnecting conduit means, including a valve controlled by a solenoid, adapted to bypass the condenser and to divert the refrigerant gas directly from the compressor to the evaporator coils, with conduit means to return the refrigerant to the compressor, and an automatic timer switch connected with an electric circuit and adapted to activate the systems alternately at pre-selected intervals; the improvement which comprises a re-evaporator chamber disposed intermediate the return conduit adjacent the compressor and adapted to receive the returning refrigerant and to retain the liquid portion thereof, heating means provided within the chamber in direct contact with the refrigerant and adapted to vaporize the liquid refrigerant therein during activation of the defrost system, and means to control the temperature within the re-evaporator chamber.

3. In an automatic refrigeration and hot gas defrost system wherein the refrigeration system comprises a compressor, a condenser, a liquid receiver, an expansion valve, evaporator coils and a heat exchanger, with inter connecting conduits therefore and conduit means for return of the refrigerant to the compressor, and the hot gas defrost system comprises interconnecting conduit means, including a valve controlled by a solenoid, adapted to bypass the condenser and to divert the refrigerant gas directly from the compressor to the evaporator coils, with conduit means to return the refrigerant to the compressor, and an automatic timer switch connected with an electric circuit and adapted to activate the systems alternately at pre-selected intervals; the improvement which comprises a re-evaporator chamber disposed intermediate the return conduit adjacent the compressor and adapted to receive the returning refrigerant and to retain the liquid portion thereof, heating means provided within the chamber in direct contact with the refrigerant and adapted to vaporize the liquid refrigerant therein during activation of the defrost system, means to control the temperature within the re-evaporator chamber and means to drain incidental oil from the chamber into the compressor.

4. In an automatic refrigeration and hot gas defrost system wherein the refrigeration system comprises a compressor, a condenser, a liquid receiver, an expansion valve, evaporator coils and a heat exchanger, with interconnecting conduits therefore and conduit means for return of the refrigerant to the compressor, and the hot gas defrost system comprises interconnecting conduit means, including a valve controlled by a solenoid, adapted to bypass the condenser and to divert the refrigerant gas directly from the compressor to the evaporator coils, with conduit means to return the refrigerant to the compress01, and an automatic timer switch connected with an electric circuit and adapted to activate the systems alternately at pre-selected intervals; the improvement which comprises a re-evaporator chamber disposed intermediate the return conduit adjacent the compressor and adapted to receive the returning refrigerant and to'retain the liquid portion thereof, a heating element provided within the chamber in direct contactwith the refrigerant and adapted to vaporize the liquid refrigerant therein during activation of the defrost system, a temperature controller adapted to control the activation of the heating element to regulate the temperature within the chamber, and a drain pipe connecting the bottom of the chamber with the return conduit for draining incidental oil from the chamber into the compressor.

5. An automatic hot gas defrost system comprising a compressor, a solenoid-controlled valve, evaporator coils, a heat exchanger, a re-evaporator chamber and a timer switch connected with an electric circuit, conduit means connecting the compressor with the evaporator coils and the heat exchanger and conduit means to return the refrigerant from the heat exchanger through the re-evaporator chamber to the compressor, the re-evaporator chamber disposed intermediate the return conduit adjacent the compressor and adapted to receive the refrigerant and to retain the liquid portion thereof, means provided Within the chamber in direct contact with the refrigerant and adapted to be activated by the timer switch to vaporize the liquid refrigerant within the chamber.

6. An automatic hot gas defrost system comprising a compressor, a solenoid-controlled valve, evaporator coils, a heat exchanger, a re-evaporator chamber and a timer switch connected with an electric circuit, conduit means connecting the compressor with the evaporator coils and the heat exchanger and conduit means to return the refrigerant from the heat exchanger through the re-evaporator chamber to the compressor, the re-evaporator chamber disposed intermediate the returnconduit adjacent the compressor and adapted to receive the refrigerant and to retain the liquid portion thereof, heating means provided within the chamber in direct contact with the referigerant and adapted to be activated by the timer switch to vaporize the liquid refrigerant within the chamber, means to regulate the temperature within the chamber and means to drain incidental oil from the chamber back into the compressor.

7. A hot gas defrost system according to claim 6, wherein the heating means within the re-evaporator chamber comprises an electrically activated element.

8. A hot gas defrost system according to claim 6, Wherein the temperature regulator comprises an electrically activated element.

References Cited in the file of this patent UNITED STATES PATENTS 

5. AN AUTOMATIC HOT GAS DEFROST SYSTEM COMPRISING A COMPRESSOR, A SOLENOID-CONTROLLED VALVE, EVAPORATOR COILS, A HEAT EXCHANGER, A RE-EVAPORATOR CHAMBER AND A TIMER SWITCH CONNECTED WITH AN ELECTRIC CIRCUIT, CONDUIT MEANS CONNECTING THE COMPRESSOR WITH THE EVAPORATOR COILS AND THE HEAT EXCHANGER AND CONDUIT MEANS TO RETURN THE REFRIGERANT FROM THE HEAT EXCHANGER THROUGH THE RE-EVAPORATOR CHAMBER TO THE COMPRESSOR, THE RE-EVAPORATOR CHAMBER DISPOSED INTERMEDIATE THE RETURN CONDUIT ADJACENT THE COMPRESSOR AND ADAPTED TO RECEIVE THE REFRIGERANT AND TO RETAIN THE LIQUID PORTION THEREOF, MEANS PROVIDED WITHIN THE CHAMBER IN DIRECT CONTACT WITH THE REFRIGERANT AND ADAPTED TO BE ACTIVATED BY THE TIMER SWITCH TO VAPORIZE THE LIQUID REFRIGERANT WITHIN THE CHAMBER. 